That seems like an abnormally high amount of CPU and Ram usage. I just loaded up BigBox with my Task Manager open on the other monitor to watch CPU and Memory usage of BigBox while I did things.
My Ram usage stayed around the 750 meg range, it did fluctuate +/- 50 megs but never going over 800. My CPU usage stayed in the single digits unless changing themes, then it did go over 25% usage but not much over and only for a short period and then settled back down into the single digits again once the theme transition was finished doing its thing.
Specs:
Windows 10, fresh install several months ago
AMD 8350 @ 4GHz, 8 cores
16 Gigs ram
Nvidia GTX 970
Everything runs off of normal run of the mill mechanical drives other than some of my larger slow to load games, those are on an SSD.